<?php
require_once 'Pizza.php';
require_once 'PizzaSingle.php';

//非单例模式
$pizza = new Pizza();
$pizza1 = new Pizza();
var_dump($pizza === $pizza1);

//单例模式
$pizzaS = PizzaSingle::getInstance();
$pizzaS1 = PizzaSingle::getInstance();
var_dump($pizzaS == $pizzaS1);
